Safety device.



E. L. GALE, Sn.

SAFETY DEVICE. APPLICAHON FILED NOV. 20, 1912.

Patented July 11, 1916.

3 SHEETS-SHEET E. L. GALE, Sir.

SAFETY DEVICE.

APPLICATION FILED NOV. 20. I912.

1,190,884. Patented July 11, 1916.

3 SHEETS-8HEET 2.

WITNESSES: b INVENTOR W ATTORNEY E. L. GALE, Sn.

SAFETY DEVICE.

APPLICATION FlLED Nov. 20, 1912.

1 1 90,884. Patented July 11, 1916.

3 SHEETS-SHEET 3.

W/ THE 885 8 INVENTOR UNITED STATES PATENT OFFICE.

ERNEST L. GALE, SR, or

YONKERS, NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

SAFETY DEVICE.

Specification of Letters Patent.

Patented July 11, 1916.

To all whom it may concern:

State of New York, have invented a new and useful Improvement in Safety Devices,

of which the following is a specification.

' normal.

My invention relates to controlling apparatus for electric. motors and more particularly to means for protecting the motor and other apparatus against continued heavy currents.

The exact nature of the invention and the objects sought to be attained will appear more fully hereinafter.

Referring to the accompanying drawings which illustrate the principles of my invention-Figure 1 is a diagrammatic view of an alternating current electric motor and controlling apparatus therefor as used in an automatic or push button elevator system; Fig. 2 illustrates a modification; Fig. 3 shows a further modification in which a motor of the squirrel cage rotor type is em ployed.

The apparatus as shown in Fig. 1, comrises an electric motor M, a main line switch A through which alternating current is supplied to the motor and controlling mechanism, reversing switches U and D controlling the phase relation of current supplied to the motor, a potential switch P. starting resistance R in the rotor circuits of the motor, electromagnetic switches E and F controlling said resistance, an electromagnetic brake B for the motor, a floor controller G, and self holding relay magnets. o, c and f in the push button circuits. The motor M receives current through the leads a, b and c, which are connected to the stator windings of the motor. The lead 6 extends directly to the main line switch A, and the leads a and 0 are adapted to be connected through the reversing switches U and D and the potential switch P to the conductors a and 0 leading to the switch A. The potential switch P comprises a self holding magnet coil 4 which maintains the switch in closed position. while the, line potential is The brake B as diagrannnatically shown. comprises a plurality of magnet coils connected to the leads a, 7) and c. The fuse 5 is interposed between the lead 7) and the brake coils. lVhen the brake is lifted it operates to close a pair of contacts 6, the latter being separated while the brake is applied. The purpose of these contacts will appear hereinafter. An electromagnetic switch E comprises contacts 7, connected to the core :3 of the magnet and adapted to be lifted 1nto engagement with stationary contacts 9. A dashpot 10 is connected to the magnet core to retard its upward movement. A pair of back contacts 11, one of which moves with the magnet core are adapted to be separated when the magnet is energized. The magnet F and associated mechanism are substantially the same as that just described in connection with the magnet E, and therefore need not be set forth in detail. It may be noted, however, that the magnet F is adjusted to be slower in operation than the magnet E. \Vhen the leads a, b and 0 are connected to receive current, the winding of the magnet E which is connected across the leads a and b is energized and said magnet operates to connect the contacts 7 and 9, and thereby short-circuit the sections 1' of the starting resistance R to which said contacts are connected. During this operation of the magnet E the motor receives current and under normal conditions is started and runs at slow speed. The short-circuitingof. the resistance 1" permits an increase in the speed of the motor. The magnet F has its winding connected across the leads b and 0 and receives current simultaneously with the magnet E but being more sluggish in operation, it does not close its contacts until the motor has accelerated as above noted, and then operates to short-circuit the remainder of the starting resistance R. K

I have shown my invention applied to a push button elevator adapted for a three story building. Push buttons 1, 2, and 3 are located at the first, second and third floor landings, respectively. Similar push buttons 1, 2 and 3 are located within the ele-. vator car C, the latter being shown at the third floor landing. The floor controller 6: comprises bridging contact pieces 12, 13, 14 and 15, adapted to be moved into and out of engagement with cotiperating stationary contacts. This controller is geared to run in unison with the motor and operates its contacts in a well known manner to control the reversing switch circuits and bring the car to rest at any desired floor landing corresponding to the push button which has been operated.

versing switch magnet.

In order to make clear the operation of the apparatus we will assume that a person in the car desires to bring the car to the second floor and therefore operates the push button 2. Assuming that the potential switch is in closed position, a circuit is established through the down reversing switch D as follows: from the main line switch A, through conductor 0' contacts 16, 17 of the potential switch, conductor 18, push button switch 2, conductor 19, through a relay magnet e and resistance 20 in parallel, conductor 21, contacts 22, 23, of the floor controller, conductor 2 magnet coil 25 of the reversing switch D, conductor 26, contacts 11 of switch E, contacts 11' of switch F, conductors 27, and I). The reversing switch D is therefore closed, the con tacts 28, 29 engaging the contacts 30, 31, respectively. This for the rotor of the motor, that is the lead a is connected through the contacts 28, 30, conductor 32, contacts 33, 34, and conductor a to the main line, and the motor lead 0 is connected through contacts 29, 31, of the switch and contacts 17, 16 of the potential switch and conductor 0' to the main line. The brake magnet at the same time receives current and operates to lift the brake and also to connect the contacts 6. The motor now starts and runs at slow speed until the accelerating magnets E and F have operated to bring the motor up to full speed as already described. As

the accelerating magnets operate, the back contacts 11 and 11' are separated and open the circuit above traced for the re- But it will be noted that the brake magnet has already operated to establish a circuit through the contacts 6 between the conductors 26 and b. As this circuit is in shunt with the contacts 11 and 11', the current through the reversing magnet is not interrupted. The relay magnet e in the circuit already traced for the reversing switch magnet operates to close the contacts 36 and establish a self holding circuit for the magnet e by way of conductors 37, 38, and contacts 36, in shunt to the push button switch 2, so that the circuit for the reversing switch magnet remains closed after the operator has released the push button switch 2. As the car nears the second floor landing, the floor controller G automatically lifts the bridging contact 14 and opens the reversing switch magnet circuit. The reversing switch is therefore opened and cuts ofi'the supply of current from the motor and brake, so that the latter is applied and the car brought to rest.

he normal operation is as above set forth. To understand the operation of my invention in protecting the 'motor, let it be assumed for example that when the motor circuits are established the mg current as usual.

completes the circuits fuse 5 of the brake blows out due to excessive current or failure of the brake to lift at once. The motor will then not be able to start although it receives as heavy a start- The accelerating magnets however receive currents and start to operate as before, but as soon as the magnet ll lifts its core, the contacts 11 are separated and break the circuit through the reversing switch magnet. The latter therefore opens the reversing switch and cuts off all current supply to the motor and controlling apparatus. I f for any other reason the brake fails to lift and close the contacts 6, the accelerating magnet or magnets will operate as above pointed out to cut off the current supply. My invention also operates as a protective device in case the operation of a reversing switch fails to close both of its pairs of contacts. If for example, the reversing switch D operates to close only the contacts 29 and 31, the contacts 28 and 30 remaining separated for any reason, the motor and brake magnet would then receive current only through the leads I) and c. The brake magnet would then receive insufiicient current to lift the brake, and the motor would also receive only a single phase of the current and would fail to start. The accelerating magnet E would not in this instance be energized, but the magnet F would receive current as usual and operate to separate the contacts 11', thus elfccting the opening of the reversing switch as before. 30 and 28 of the reversing switch D were brought together, the brake would fail to operate and the accelerating magnet E would open the reversing switch magnet circuit. Various other conditions may prevent the motor from starting. For instance a main fuse may blow, or the primary leads may all be connected to receive normal current in all the phases, but some trouble in the secondary or rotor circuits prevents the motor from starting, or the rotor may freeze to the stator. It will be seen that in any of the above events or if for some other reason the motor fails to start, my invention operates to cut off the current supply and prevent the motor and other apparatus from burning out or receiving a continued heavy current.

To, show the advantage of my invention as used in connection with an automatic or push button elevator system, we will assume that one of the push buttons has been operated to establish the reversing switch magnet circuit. If in such event the brake fails to lift and the motor does not start the current supply will be cut off as above explained and the controlling apparatus restored to its normal condition of rest. Without my invention, however, the motor and other apparatus would receive a heavy In like manner if only the contacts current which might be continued all night or for an indefinite period as the person operating the push button having failedto start the car would leave the same with. the motor circuits closed. This would probably result in the motor being burned'out or destroyed in addition to the great waste of energy. i

I have described my invention'in connection with the operation of the down reversing switch D, but it. will be understood that theoperation is the same in principle when the up switch U is operated. In the latter instance the motor leads a and c are connected respectively to theconductors c and a. so that the phase relation of the motor currents is reversed, causing the motor to operate in the opposite direction. The push button switches 1, 2 and 3 at the floor landings 'are in parallel with the switches 1, 2 and 3, in the ear. to simplify the illustration and description I have omitted from the-drawings the usual devices for preventinginterference between the switches in the car and those at the floor landings. The various safety devices such as the limit switches at the upper and lower ends of the hatchway, the slack cable switch, the emergency switch in the car, the door contacts,ete., have been omitted asthey are unnecessary to illustrate my invention- Fig. 2 shows a modification in which the manual control is effected bymeans of a standing rope '40 extending through: theelevator car C. The rope40 extends around guide sheaves 41, 42 and 43, and around an operating sheave 44' fixed to the shaft 4:"), to which also is secured 'an. operating lever 46. The lower end. of-said lever is in operative engagement with reversing switch 47. The upper end of the lever 46 is connected by a pivot 48 to a link 49 which controls a lever 50 having a pivot 51-. The

starting resistances :1 1 and z are'connected respectively across the leads 52 and 53, 52 and 54, 53 and 54, in the rotor circuit of the motor. The lever 50 carries end sections or brushes 55 and 56, adapted to slide over contacts connected to the resistances 1 and 2. These brushes are connected, by a conductor 57, but are insulated from the main portion of the lever 50. \Vhen the parts are in the position shown, the lever 50 is locked by means of the slotted link 49 which engages a pin 58 on the lever. \Vhen the lever 46 is rotated in either direction, the link 49 is drawn downward permitting the lever 50 to operate. A spring 59 rotates the lever 50 to cut out the starting resistance, such movement being retarded by the dashpot 60. A check valvefil in the dashpot permits the lever to rotate freely in the reverse direction.- Stops 62 limit the movement of the lever 46. The switch 6 controlled by the brake magnet is in this instance connected the lead a.

In order influence of the spring -and (3S,- and theresistance 2 through the conlever 50 disconnects it from the contact (37.

in series with the potential switch coi The circuit for said switch may be tr: from the lead a, through the contacts 2&3, coil 4 of the potential switch, conduc; ($5, switch 6, conductor 66, contacts a (33, and 17, 1(3, of the potential switch A shunt circuit across switch (3 is provided by a Contact (37 in e -gagement with the lever 50, said cont: and lever being connected respectively the conductors (35 and (36.

The operation will be understood in the followingstatement The parts are i their normal position of rest, if-we'assum the potential switch to be closed. The oper ator in the ca r operates the hand rope 4.0 t rotate the sheave 44 and controlling love 46 in a direction depending on whether it desired to move the car up or down. '1 i reversing switch 47 is operated in the coli responding direction to establish circuit con nections for the stator ofthe motor. At tli same time the link 49 is drawn downward,-. and permits the rheostat lever 50 under. the- 5!) lmtretarded the dashpot to gradually short circuit the'l resistz'mces m 1 and 2. The resistance w isshmt-circuitcd through the conductor 7, the rcsistan(-.e- 1 through the conductors 57 dnctor (38. The movement of the rheostat and opensthe shunt circuit aeross the switch 60.- Under normal conditions the hrakewhich receives current when the reversing switch is closed, operates to close the switch- (3 before said shunt circuit is opened, so that the potential switch'rcceives current without interruption. If, however, thebrake magnet for any reason fails to lift the 10:, brake and close the switchli, the circuit for the potential switch magnet will be interrupt-ed at the contact ("7 so that the potential switch will open and cut oil all current sup-j ply to the motor and controlling apparatus.

Fig. 3 illustrates my invention, in connection with a system comprising a motor M of the squirrel cage rotor type. In this arrangement a manual controlling lever is placed in the elevator car. A switch 71 is connected in parallel with-the switch (3 in the circuit for the reversing switch magnets. The switch 71 is closed by a spring 72', and is adapted to be opened by an electromagnet 73. A dashpot 74 retards the upward movement of the magnet core. A dctent 75 carried by the magnet core is adapted to engage the switch lever and open the switch 71. The circuit for the magnet 73 is controlled by the reversing switches.

In operation, if the car switch 70 is moved for example to the left. a circuit is established for the magnet of the down rcversing switch D, which circuit may be traced from the main 0', through the potential switch contacts 16, 17, assuming the potential switch to be closed, through condoctor 76, car switch 70, contact 77, conductor 78, magnet coil 25 of the reversing switch D, through the switch 71 and to the lead I). The reversing switch D therefore operates to establish circuits for the motor and brake magnet. A circuit is also completed for the magnet 73, which circuit may be traced from the lead I), through the magnet coil, conductor 79, contacts and S1, of the reversing switch and conductor S2 to the main 0'. The magnet 73 therefore operates to lift its core retarded by the dashpot 74 and opens the switch 71. In the meantime the brake magnet operates to close the switch 6 if conditions are normal. 'If the brake magnet fails to operate, the circuit of the reversing switch magnet is interrupted and the reversing switch opens to cut otl' the current supply. The operation is substantially similar to that fully set forth in connection with Fig. 1.

It will be understood that my invention is adapted for use with other types of elevators than those herein shown. It is also adapted for use with controlling systems in general, whether connected with elevators or employed for operating other kinds of mechanism. I wish it to be further understood that my invention is not limited to the details or construction or arrangement of parts herein disclosed, and that various modifications might be made within the spirit and scope of the invention.

'hat I claim is 1. The combination of an electric motor,

3. The combination of an electric motor a brake, a switch operated by the brake to maintain the circuit to the motor, said switch operating only when the brake is released, and means tobreak the circuit to the motor and maintain it broken unless said switch is operated.

4.. The combination of an electric motor, a brake therefor, a switch operated by the brake to maintain the circuit to the motor, said switch operating only when the brake is released, and means to break the circuit to the motor and maintain it broken unless said switch is operated:

The combination of an electric motor, a brake therefor, a switch operated by the brake to maintain the circuit to the motor, and means to break the circuit to the motor and maintain it broken unless said switch is operated.

6. The combination of an electric motor, a switch for opening and closing the motor circuit, a brake, and means operated by the brake to maintain the switch in closed position.

7. The combination of an electric motor, an electromagnetic switch through which current is supplied to the motor, brake mechanism, and means associated therewith to maintain the circuit of the switch magnet.

8. The combination of an electric motor, a switch through which current is supplied to the motor, an electromagnet to operate said switch, brake mechanism, and a switch in circuit with said eleetromagnet and arranged to be closed by the brake mechanism.

9. The combination of an electric motor, a reversing switch,'an electromagnetic brake, and means to open the reversing switch when the brake is not released,'to open the circuit to the motor and maintain it open.

10. The combination of an electric motor, an electromagnetic switch through which current is supplied to the motor, brake mechanism, a switch in circuit with the magnet winding of said first named switch and operated by the brake mechanism, and means to establish a circuit through the said magnet winding independently of said second named switch.

11. The combination of an electric motor, an electro-responsive device, through which current is supplied to the motor and said electro-responsh'e device, and means operable after said switch is closed automatically to open said switch upon failure of the said electro-responsive device to operate.

12. The combination of an electric motor, an electromagnetic switch through which current is supplied to the motor, parallel circuits in series with the magnet winding of said switch, switches in said circuits, and means for operating said switches.

13. The combination of an electric motor, an electro-responsive device connected in} parallel to the motor, an electro-magnetic switch through which current is supplied to the motor and said device, switch contacts in circuit with the switch magnet winding and adapted to be brought together by the operation of said electrowesponsive device, a switch in parallel with said switch contacts, and retarded means to open said lastnamed switch when current is supplied to the motor.

14. The combination of an electric motor, brake mechanism, accelerating apparatus, and interdependent means associated with the brake mechanism and accelerating apparatus to open and close the current supply to the motor.

15. The combination of an electric motor, brake mechanism, accelerating apparatus and means dependent upon the operation of a switch current is supplied to the motor, an electromagnet adapted to operate said switch, accelerating mechanism, means operated thereby to open the electric circuit of said electromagnet, and means operated by the brake mechanism to establish a parallel circuit for said electromagnet.

' 18. The combination of an electric motor, accelerating mechanism operable independently of the speed of the motor, and means controlled by the accelerating mechanism to cut oii the supply of current to the motor.

19. The combination of an electric motor, an electro-magnetic reversing switch, brake apparatus, an accelerating magnet, a safety swltch in circuit with the reversing switch magnet and adapted to be operated by the accelerating magnet, and a switch in parallel with said safety switch and adapted to be operated by the brake apparatus.

20. The combination of a multi-phase alternating current electric motor, a multiphase brake magnet connected in parallel to the motor and means independent of the brake to cut ofi the current supply upon failure of the brake to operate.

21. The combination of a multi-phase alternating current electric motor, a main line switch, and means independent thereof and comprising an accelerating switch for automatically opening the motor circuit when the motor receives only a single phase current.

22. In combination, a multiphase electric motor, a main line switch, and means independent thereof and comprising an accelerating switch for automatically disconnecting the motor from its source of current supply if one of its leads is disconnected.

23. In combination, a three phase motor, a main line switch therefor, and means independently thereof and comprising an accelerating switch for automatically protecting the motor against a protracted flow of single phase current.

24. In combination, a multi-phase motor, a multi-phase brake magnet inoperative when impressed witha single phase voltage, and means associated with the brake magnet to protect the motor against a continued current when the brake fails to opcrate;

25. The combination of a multiphase electric motor and a brake magnet connected in parallel, said motor and brake magnet being inoperative with a single phase current, accelerating electromagnets having their windings connected across different leads of the motor, and means associated with each of said electromagnets to cut 011' the current supply from the motor and brake magnet,

when the brake fails to operate.

26. The combination of a multi-phase electric motor, a brake, a multi-phase brake magnet connected in parallel with the motor, reversing switches through which current is supplied to the motor and brake magnet, accelerating mechanism comprising magnets having their windings connected across different leads of the motor, switches connected to said mechanism and adapted to be opened by the operation of said mechanism, reversing switch magnets, a circuit therefor extending through said last named switches, and a switch in parallel with said switches and operated by the brake.

27. In an electric elevator system, the combination of an electric motor, an electromagnetic brake therefor, a through which current is supplied to the motor and brake, means to operate said switch, and means automatically to open said switch upon failure of the brake magnet to lift the brake when said switch is closed.

switch 28. The combination with an electric mo- I tor, of an electromagnetic reversing switch, a brake magnet, an accelerating swltch magnet, at dashpot connected thereto to retard its 7 ERNEST L. GALE, Sn.

operation,

Witneses:

Fmnmcx E. Hnmmm, Enwm H. S101. 

